Synthesis and functionality of dendrimer with finely controlled metal assembly

AbstractIntegrated research on the synthesis and functionality of macromolecular metal complexes has suggested that dendritic structures exhibiting a geometrical density gradient also impart a potential gradient within the constituent molecules. Focusing on dendritic π-conjugated macromolecules containing azomethine (imine) as a metal assembly site, the stepwise radial complexation of metal ions in a dendritic phenylazomethine structure has been identified for the first time. Using this discovery, the first macromolecules with precision control of the number and position of metal molecules have been synthesized. A series of new physicochemical discoveries have followed from this success, related to stepwise radial complexation, one-step multi-electron transfer, and potential gradients. The usefulness of these new macromolecules as a nano-material has also been demonstrated through application to (1) polymer electroluminescent devices, (2) organic solar cells with high energy conversion efficiency, and (3) the storage and release of metals in a manner similar to ferritin protein

A fluorescent microporous crystalline dendrimer discriminates vapour molecules

A self-assembled crystalline microporous dendrimer framework (MDF) exhibits novel turn-on and ratiometric fluorescence upon exposure to solvent vapours. The donor–acceptor character, combined with the large surface area (>650 m2 g−1), allows the MDF to discriminate vapours of volatile solvents with turn-on and colour change of photoluminescence

Periodicity of molecular clusters based on symmetry-adapted orbital model

The periodic table has always contributed to the discovery of a number of elements. Is there no such principle for larger-scale substances than atoms? Many stable substances such as clusters have been predicted based on the jellium model, which usually assumes that their structures are approximately spherical. The jellium model is effective to explain subglobular clusters such as icosahedral clusters. To broaden the scope of this model, we propose the symmetry-adapted orbital model, which explicitly takes into account the level splittings of the electronic orbitals due to lower structural symmetries. This refinement indicates the possibility of an abundance of stable clusters with various shapes that obey a certain periodicity. Many existing substances are also governed by the same rule. Consequently, all substances with the same symmetry can be unified into a periodic framework in analogy to the periodic table of elements, which will act as a useful compass to find missing substances